What is the ruling on eating food that contains non-halal meat, presented by a non-Muslim, with my knowledge of this?

Doubt regarding the permissibility of a slaughtered animal necessitates the prohibition of its meat. How much more so if you know it to be forbidden! There is no doubt that what is obligatory is to abstain and to meticulously seek out lawful meat. So, fear Allah concerning what enters your stomach, and beware lest your body grows from unlawful meat.